Seat belt webbing in a vehicle often has a shoulder belt portion for restraining forward movement of the torso of a vehicle occupant. In many vehicles, the shoulder belt portion of the webbing extends through a D-ring which is secured to the body of the vehicle at a location adjacent to the shoulder of the vehicle occupant. It is desirable to adjust the position of the D-ring relative to the vehicle occupant for the comfort of the vehicle occupant.
U.S. Pat. No. 4,538,832 discloses an apparatus for adjusting the height of a D-ring through which seat belt webbing extends in a vehicle seat belt system. The apparatus disclosed in the '832 patent includes a sliding member on which the D-ring is mounted. The sliding member is located in a bracket, and has a knob with which a vehicle occupant can move the sliding member vertically in the bracket. The sliding member carries a pair of locking pawls which are spring biased toward pairs of opposed apertures in the sides of the bracket. When the vehicle occupant moves the sliding member vertically to a location in which the locking pawls are located adjacent to a pair of opposed apertures in the bracket, the locking pawls move into the opposed apertures. The locking pawls then hold the sliding member at that location until the sliding member is again moved by the vehicle occupant. The vehicle occupant can thus move the sliding member and the D-ring vertically into any one of the locations defined by a pair of opposed apertures in the bracket.
U.S. Pat. No. 4,702,494 also discloses a device for adjusting the height of a D-ring through which seat belt webbing extends in a vehicle seat belt system. The device disclosed in the '494 patent includes a horizontal shaft on which the D-ring is mounted. The shaft is movable vertically along a guide rail. One end of the shaft supports a knob with which a vehicle occupant can rotate the shaft manually. The other end of the shaft supports a drum. An elongate connecting line is wound around the drum. An upper portion of the connecting line extends upward from the drum, and has an upper end connected to the vehicle. A lower portion of the connecting line extends downward from the drum, and has a lower end which is also connected to the vehicle. When the vehicle occupant rotates the knob on the end of the shaft in one direction, the drum on the other end of the shaft is wound onto the upper portion of the connecting line. The shaft is thus moved upward along the guide rail. When the vehicle occupant rotates the knob in the opposite direction, the drum is wound onto the lower portion of the connecting line. The shaft is thus moved downward along the guide rail. The D-ring, which is connected to the shaft, is thus moved vertically by the vehicle occupant to any location between the ends of the connecting line.